**5.1 Physical methods**

Physical methods partially eliminate pesticide residues from grapes and wines are used on a small scale in the wine industry. Most of these techniques are not economically feasible for most small to medium size winemakers, even if nowadays, the modern beverage processing technologies aim at beverages safety and sustainable production.

**Figure 3.** *Removal of pesticides from grapes and wines.*

*Management of Pesticides from Vineyard to Wines: Focus on Wine Safety and Pesticides Removal… DOI: http://dx.doi.org/10.5772/intechopen.98991*

**Pulsed electric field (PEF)** method is an emergent non-thermal technology that induces a lower degradation of compositional and sensorial characteristics than the classical thermal processing. This method uses an electric field in the form of short or high voltage pulses. The beverage is placed into the electric field, between two electrodes for a short period, regularly in the microsecond scale [56].

Zhang et al. [57] reported that PEF method in apple juice can reduce the content of diazinon and dimethoate. The efficacity of PEF can be improved with increased process time and the strength of the electric field. Efficient removal of diazinon (47.6%) and dimethoate (34.7%) was realized when using 20 kV cm − 1 for 260 μs.

Delsart et al. [58] studied the impact of the same treatment on vinclozolin, pyrimethanil, procymidone, and cyprodinil in wine samples. Results revealed that PEF method can decrease the fungicide content and the major factors of influence were the electrical field strength and used energy level.

**Ultrasounds** represent a promising innovative and green method, which offers numerous advantages, such as simplicity, cheap, energy-saving. The principal limitations of this technique and its wide use in the industry can be solved by combining it with other compounds or treatments.

Ultrasonic dishwasher is a recent technique used in elimination pesticides from fruits and vegetables [59]. Ultrasonic waves provoke a phenomenon such as cavitations, which leads to the fast formation and violent collapse of micron-sized bubbles in a liquid medium. This method with tiny implosions that ensure the cleaning power, using the ultrasonic washing, was not exploited to its maximum potential. In a recent study, Zhou et al. [60] investigated the ultrasonic washing process to eliminate pesticides from grapes. Washing with the ultrasonic dishwasher proved to be more efficient for pesticides removal. Results showed residues decreased rates between 72.1% and 100% on grapes when comparing with normal water washing**.**

Another very promising emerging technology used for grape products is **microfiltration**. This method uses a membrane technology driven by pressure and, up to date has found many practical applications for pesticides reductions, offering several technological advantages [61]. Among the advantage of microfiltration are the high separation efficiency, low energy consumption, easy implementation and operation, absence of phase transition and non-use of additional solvents, which favor the solute recovery. Doulia et al. [62] investigated microfiltration in process of elimination of pesticides from a Greek wine, utilizing six membranes with the same pore size 0.45 μm. The membranes used were: cellulose acetate (CA), cellulose nitrate (CN), regenerated cellulose (RC), polyethersulfone (PESU), polyamide (PA) and nylon (NY). Results on the effectiveness of pesticides removal were as follows for white wine: cellulose acetate > cellulose nitrate > polyethersulfone > nylon > regenerated cellulose > polyamide and for red wine: cellulose acetate > cellulose nitrate > regenerated cellulose > polyethersulfone > polyamide > nylon. Another aspect found by the authors was that the bigger hydrophobicity and the lower hydrophilicity of pesticide, the higher the microfiltration effectiveness for both wines. Moreover, Doulia et al. [62] showed that the hydrophobic pesticide removal is more effective in red wines than in white wines, for all six membranes. This seems to be caused by the presence of higher amounts of hydrophobic polyphenolic compounds in red wine.

#### **5.2 Physical: chemical methods**

One of the known methods for pesticides removal is the chemical adsorption. This method is described as eco-friendly, low production of by-product waste and cost-effectiveness. Various types of adsorbents such as clay, activated carbon, biochar and nanoparticles have been used for the adsorption of pesticides from grapes and wines. Adsorption techniques can be chemical, as bonding through ion-dipole interactions, weak Van Der Waals, forces, dipole–dipole, cation exchange and strong covalent bonding or physical adsorption [63]. Effective removal of pesticide residues depends on the pesticides concentrations, the wine fining agents, the type of compounds and the dosage.

**Ozone (O3) treatment** is a new modern technique with various uses in food and beverage industry like as pesticide removal, water remediation and decontamination of fresh fruits. Ozone has been accepted by the World Health Organization (WHO), Food and Drug Administration (FDA) and by the Food and Agriculture Organization of the United Nations (FAO) for usage as an antimicrobial agent for the treatment, storage and processing of foods in gas and aqueous phases in 1997 [64]. Since that time the ozone treatment has been utilized in the agri-food-beverage sectors, in particular to control postharvest decay and extend shelf-life of fruits and vegetables [65]. It was shown that postharvest ozone treatments improve resveratrol and other phenolic compounds [66] and decrease pesticide residues [67].

Ozone can be used in various forms such as dry, watery and moist during the decontamination method. O3 in the beverage processes is used as an oxidant for pesticide content reduction. The percentage of pesticide removal depends on the ozone characteristics and not only on the chemical pesticides composition. Thus, it is obvious that specific conditions are necessary for the effectiveness of the ozonation process. The elimination of pesticides is influenced by different conditions of application (pH, temperature and humidity), organic matter content, ozone concentration, production rate and form of application (aqueous and gaseous) [68].

The principle of this technique consists of ozone generation by the passage of air, or oxygen gas through a high-voltage electrical discharge or by ultraviolet light irradiation [69]. The product of ozone degradation is oxygen; thus, it leaves no residues on treated items. There are other possible benefits of ozone, like the elimination of mycotoxins [65], pesticide residues and microbiological control of food products [70].

In 2015, Dordevic and Durovic-Pejcev [71] affirmed that juice processing may eliminate the pesticide amounts by using washing/cleaning, pulp-removing, pressing, squeezing, clarification (like centrifugation, enzymatic treatment and filtering) and heat treatment (like boiling, pasteurization and sterilization). Botondi et al. [72] suggested to utilize ozone fumigation postharvest, in order to analyze microorganisms and evaluate the influence on polyphenols, anthocyanins and cell wall enzymes during the grape dehydration for wine production. Ozone treatments decreased yeasts and fungi by 50%. Moreover, a treatment that used shock ozone fumigation before dehydration decreased the microbial count during dehydration without influencing the polyphenol and carotenoid amounts. In 2018, Karaca [73] studied the removal of pesticides from grapes by exposing fruits in ozone-enriched air. Gaseous ozone rich atmosphere led to a 2.8-fold higher removal of azoxystrobin fungicide than control sample. Both phases, gaseous and aqueous ozone techniques displayed 67.4% and 78.9% decrease of chlorothalonil residues from table grapes [74]. The differences in the efficacity of pesticide residues may be assigned to the diversity in the structure of the pesticides.

**Activated carbon (AC)**, is generally used in winemaking to remove phenolic compounds, pigments and off-flavors. AC has high and broad affinities especially for benzoid and non-polar substances. Activated carbon shows large positive effects on reduction of pesticides, due to its high adsorption capacity, large surface area and high porosity.

Sen et al. [75] studied the influences of activated carbon with low, middle, high doses on the removal of vinclozolin, penconazole, endosulfan, imazalil, nuarimol

and tetradifon used in viticulture. The amount of imazalil decreased in white wine with middle and high doses of activated carbon, but low dose of activated carbon removed 92.96% of imazalil. This result can be associated to the high adsorption surface of carbon and to the limited interference from the wine chemical compounds.

Nicolini et al. [76] investigated whether small amount of pesticide residues can be removed adding a low dose of activated carbon during fermentation. AC decreased up to 130 μg/L of fungicides in the white wine samples studied. Results obtained in wines fermented with activated carbon had 30–80% lower fungicides as compared to the control. An exception was found in the case of iprovalicarb which did not significantly decreased.

**Bentonite** is a natural montmorillonite clay and in nature has Mg++, Ca++, Na+ , aluminum and silicon oxide forms. The most used form of bentonite in winemaking is sodium bentonite, which has a large adsorption surface. This surface has a strong negative charge, and it allows ion exchanges and other electrostatic interactions. Bentonite sodium is used largely in winemaking for the elimination of positively charged proteins. Among the disadvantages of bentonite are the nonselective elimination process and the reduction of valuable aroma compounds from wines [77, 78].

Sen et al. [75] reported that bentonite had a major effect on decreasing the concentrations of imazalil (96–98%), endosulfan (81–87%), and penconazole (84–95%). However, bentonite influence on nuarimol and tetradifon was limited, removing between 15 and 33% and 25–39%, respectively. Bentonite had no influence on the elimination of vinclozolin. Ruediger et al. [79] has shown that 500 and 2500 mg/l of bentonite eliminated a large amount of pesticides from white wines. The authors have found that there was not a clear effect of an increased dose of bentonite on triadimenol and metalaxyl.

Navarro et al. [80] showed that filtration of wines, previously clarified with bentonite and gelatin, lead to the removal of 2% metalaxyl, 7% fenarimol, 25% penconazole and 28% vinclozolin. During maceration stage, the rate remaining of chlorpyrifos, penconazole and metalaxyl was 90%, while the percentage of fenarimol, vinclozolin and mancozeb was lower (74–67%).

Likas et al. [81] reported that processing of treated grapes into wine almost removed residues for flufenoxuron and lufenuron resulting in residue-free wine, whereas tebufenozide was found in wine at concentrations from 0.13 to 0.26 mg/L. Among the fining agents used, bentonite, potassium caseinate, gelatine–silicon dioxide and polyvinylpolypyrrolidone did not actually eliminate residues from wine, while charcoal very effectively removed tebufenozide residues. The pesticide residues in grapes presented a low removal for 42 days after phytosanitary treatment, with dissipation rates varying from 0.011 to 0.018 mg/kg day. The pesticide residues have shown for 0.27 mg/kg for flufenoxuron, lufenuron and 0.68 mg/kg for tebufenozide, and their concentrations were lower than the maximum residue limits (MRLs).

**Chitosan** is a biopolymer obtained from chitin and comprises N-acetylglucosamine and glucosamine units. These properties of the chitosan structure give its flexibility and heterogeneity. Hydrophilic functional groups cannot alter chitosan's hydrophobic nature and support adsorption [82].

Venkatachalapathy et al. [83] studied the pesticide removal efficacy, when using chitosan fining agent in grape juice during the clarification stage. In this study, pesticide removal efficiency of chitosan ranged from 54–72% at 0.05% chitosan concentration, and increased up to 86–98%, when higher chitosan concentration was used (up to 0.5%). Results showed that 0.05% chitosan had the highest pesticide removal efficiency (72%), when compared other clarifiers. Also, investigations showed that

the optimal pesticide elimination was achieved using chlorpyrifos (98%) and ethion (97%) at chitosan for 1 h incubation continued by phorate (96%), fenthion (95%), fenitrothion (94%) and diazinon (86%) at chitosan for 2 h incubation time.

In recent years, a new carbon rich adsorbent (38–80%), **biochar**, attracted remarkable attention. Biochar is produced by thermal conversion under oxygen free environment [84]. Yuan et al. [84] expressed that the biochar surface brings negative charges because of the occurrence of organic groups. Biochar can be used for the elimination of different toxic compounds such as pesticides, heavy metals, antibiotics and dyes. Biochar has unique characteristics such as higher pore volume, larger surface area, high environmental stability, low cost and extensive raw material sources [85]. Moreover, other materials like clay, zeolite, mesoporous materials were also used for the removal of pesticides from grapes and wines.

Grape pomace (GP) is a by-product of various grape based manufacturing processes, such as juice, jam-making, wines, etc. The GP biomass represents around 20–30% of the residual biomass of grapes. European countries reported GP wastes of about 1,200 tons per year. Yoon et al. [86] investigates in his work the adsorptive comportment and mechanisms of grape pomace-derived biochar (GP-BC). Pesticide cymoxanil removal rates were assessed during this study. Biochar produced at 350°C achieved the maximum adsorption capacity of 161 mg CM/g BC at pH 7 for cymoxanil. Thus, cymoxanil adsorption was attributed to the combined influences of metal and hydrophilic interaction.

Angioni et al. [44] has researched the transfer from grapes to wines during the entire winemaking process for some pesticides. The concentrations found in grapes were under limits set by the EU, having the amounts 0.81, 0.43, and 4.23 mg/kg for iprovalicarb, indoxacarb, and boscalid, respectively. The obtained results showed that all pesticides have been transferred from grapes to the must, whereas in wines the residues were insignificant. For pesticides, the clarification stage presented a good elimination of these toxic compounds from wines.

#### **5.3 Oenological techniques**

Winemaking processes have the potential to remove, degrade or decrease pesticides content in grapes. This is achieved mainly through stages of winemaking, such as pressing, filtration, adsorption or through microbial processes occurring during the fermentation stage [87, 88].

In the first stages of winemaking, in pressing and maceration process, the pesticide residues on grapes are decreased notably. Thus, a considerable amount of toxic compounds remain in the cake and lees, and a small quantity migrates into the must [89]. In the next stage, in alcoholic and malolactic fermentation, yeasts destroy some part of pesticide residues. Another important stage in which takes place the reduction of pesticide residues is the clarification step [90].

Pan et al. [91] found that the whole process can reduce the zoxamide residue in red and white wines. Peeling process has an important influence on the decrease of zoxamide, because a high content of this pesticide was retained by the grape skin. These results can provide more accurate risk assessments of zoxamide during winemaking process. Pazzirota et al. [92] found that pesticide distributions over the different stages of winemaking process were clearly dependent on the affinities of pesticides to organic or aqueous fractions in the process. The pesticide contents decreased from grape to wine. Decreases from fermentation stage during maceration are due to pesticide affinities for solid residues present in the sample for cyprodinil and imazalil.

Yeast have the ability to decrease pesticide residues from wines, by degradation and/or adsorption. The removal of pesticides during winemaking has been widely studied [93]. In this process, the main agent for adsorption is the yeast cell wall,

*Management of Pesticides from Vineyard to Wines: Focus on Wine Safety and Pesticides Removal… DOI: http://dx.doi.org/10.5772/intechopen.98991*

containing polysaccharides as basic building blocks. It has been shown that the principal fraction of mannoproteins is released in the first week after the alcoholic fermentation has finished. In this stage the dominant adsorptive action is noticed. Also, at the end of the alcoholic fermentation, *bâtonnage* is used to obtain higher quality wines. The mannoproteins are released and the adsorption of pesticides take place [94]. However, not only strain properties, but also differences in the binding affinity of pesticides, are important factors. The adsorption of yeast lees is different among strains, and due to the cell wall structure, physicochemical conditions, especially pH, influence the adsorption ratio [94].

Elimination of pesticides by degradation is an uncommon process. Yeast have the ability to degrade some pesticides from the pyrethoid class and insecticides thiophosphates class [95]. During fermentation, yeasts partially degraded quinoxyfen and adsorbed it completely [89]. It is been shown by Cabras et al. [89] that fenhexamid did not affect alcoholic fermentation, whereas a great content of pyrimethanil (10 mg/L) was found to significantly diminish the anaerobic growth of *Hanseniaspora uvarum* [96]. In other studies, the presence of pesticides has been found to stimulate yeasts, especially *Kloeckera apiculata*, which produced more alcohol [97]. Oliva et al. [98] found that no fungicides delays or inhibits fermentation processes. Also, the evolution of yeast populations during fermentation follows the normal multiplication processes of the species.

### **6. Conclusions**

Increased population, higher demand from quality beverages, rapid climatic changes and the need for more phytosanitary treatments constitute to a wine industry that has to focus more on sustainable practices, high grape yields and minimized health risks. Conservator winemakers that use adequate agricultural practices can limit potential negative effects that are linked to higher pesticide concentration in wines. However, the high pressure of climatic conditions, increased pathogen virulence and mutations into new variants can increase the quantities of pesticides needed in vineyards and led to potential human health risks. Large pesticide quantities may affect negatively the water and soil quality, leading to undesired effects on the animals, plants and human communities.

Different techniques have been used successfully to remove pesticide residues form grapes and wines. Technologies such as pulsed electric field (PEF), ultrasounds (US), microfiltration, ozone (O3), adsorbents used during pressing, fermentation and filtration are nowadays implemented by many winemakers. However, preventive methods applied directly from vineyards and emergent technologies should be utilized to produce grapes with tiny amounts of pesticides. Effective pesticide management requires actions supported by a very clear and transparent legal system and toxicity regulations.

Integrated pest management strategies could provide a more efficient control of pesticides use and limit the residues. Utilization of precision spraying and local treatments can reduce the pesticide residues negative impact on the environment and potential human health risks.

### **Acknowledgements**

This work was supported by a grant of the Romanian Ministry of Education and Research, CNCS – UEFISCDI, project number PN-III-P1-1.1-PD-2019-0652, within PNCDI III.

*Grapes and Wine*
